1. Field of the Invention
The subject invention generally relates to a steering column assembly, and more specifically to an adjustable steering column assembly.
2. Description of the Prior Art
Steering column assemblies are often adjustable in a longitudinal direction, i.e., a telescopic adjustment, and/or adjustable in a vertical direction, i.e., a rake or pivot adjustment. Typically, the adjustable steering column assemblies include a mounting bracket configured for attachment to the vehicle, and a column jacket coupled to the mounting bracket. The column jacket extends along a longitudinal axis, and is moveable relative to the mounting bracket in at least one of a vertical direction, to adjust the rake adjustment, and a longitudinal direction, to adjust the telescopic adjustment.
The steering column assemblies may utilize one or both of a frictional clamp and an interlocking toothed mechanism to secure the relative position of the column jacket relative to the mounting bracket. The frictional clamp compresses the mounting bracket against a compression bracket, attached to the column jacket, to generate a frictional force to secure the position of the column jacket. However, in the event of an impact event, such as a vehicular collision, the frictional force may be insufficient to secure the position of the column jacket relative to the mounting bracket. Accordingly, many steering column assemblies alternatively utilize, or in combination with the frictional clamp, an interlocking toothed lock mechanism to mechanically lock the position of the column jacket relative to the mounting bracket.
Typically, such interlocking toothed lock mechanisms include one of the mounting bracket and the compression bracket defining a rake slot and a telescope slot respectively. The rake slot and/or the telescope slot define a plurality of slot teeth. A shaft, i.e., a rake bolt, extends through the rake slot and/or the telescope slot. A lock, i.e., a pawl, is disposed within the rake slot and/or the telescope slot, and includes a plurality of lock teeth. A lever is coupled to the shaft to rotate the shaft. Rotation of the shaft moves the lock into and out of a locked position, wherein the lock teeth are disposed in mechanical interlocking engagement with the slot teeth, and an unlocked position, wherein the lock teeth are disengaged from the slot teeth. The interlocking mechanical engagement between the lock teeth and the slot teeth prevent slippage of the column jacket relative to the mounting bracket, even in response to a collision event.
When moving the lock into the locked position from the unlocked position, the lock teeth often engage the slot teeth in peak-to-peak engagement. When this happens, the column jacket must move relative to the mounting bracket to permit a complete or full meshing engagement between the lock teeth and the slot teeth. If the steering column assembly includes a frictional clamp, the frictional force generated and applied between the mounting bracket and the compression bracket at the time of the peak to peak engagement between the lock teeth and the slot teeth may be sufficiently high to prevent the movement of the column jacket relative to the mounting bracket to obtain the full meshing engagement. Failure to achieve the full meshing engagement provides a false sense that the steering column assembly has fully engaged both the frictional clamping mechanism and the interlocking toothed lock mechanism.